$ { \left[\begin{array}{rr}{-1} & {3} \\ {4} & {2} \\ {0} & {2}\end{array}\right]+\left[\begin{array}{rr}{-2} & {0} \\ {3} & {0} \\ {0} & {-1}\end{array}\right] = {?} } $
Answer: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rr}{-1}+{-2} & {3}+{0} \\ {4}+{3} & {2}+{0} \\ {0}+{0} & {2}+{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-3} & {3} \\ {7} & {2} \\ {0} & {1}\end{array}\right]}$